The field of the present invention is ultrasonic transmitters and, more particularly, ultrasonic pest control devices and methods for constructing the same.
It is well known that pest infestation is a primary cause of damage to stored materials and foodstuffs each year, and that damage resulting from pest infestation causes the agricultural and food and beverages industries, both in this country and worldwide, to suffer substantial losses each year. In addition, it is well known that many pests, including rodents, insects, and birds, find ultrasonic sound waves of certain frequencies to be disturbing or unpleasant, and that under the right conditions ultrasonic sound waves may be used to drive pests away from a given area. For this reason, numerous electronic and mechanical ultrasonic pest control devices have been developed as a means for driving pests away from food and materials storage facilities. However, these prior devices have not proven to be as reliable, economical to manufacture, and capable of ready adaptation to a broad range of environments as is desirable.
For example, those skilled in the art will appreciate that electronic ultrasonic pest control devices are prone to damage and disfunction at preferred output intensities. More specifically, it has been found that to drive pests away from a given area it is preferable to bathe the area in ultrasonic waves having a magnitude of at least 100 db, and that, while some electronic devices are capable of bathing small areas in ultrasonic waves of sufficient magnitude, these devices simply will not withstand operation at output intensities sufficient to cover large areas.
With respect to non-electronic ultrasonic pest control devices, those skilled in the art will appreciate that the issue is not operability or reliability, as numerous ultrasonic whistles have been developed and are capable of producing ultrasonic outputs in the magnitude ranges suggested above. Instead, the issues are cost, ease of manufacture, and ease of customization to a given area or volume of interest. As shown in U.S. Pat. No. 3,138,138, issued to Quittner (hereinafter the "Quittner patent"), and in U.S. Pat. No. 3,277,861, issued to Moe (hereinafter the "Moe patent"), conventional ultrasonic "whistle based" devices generally comprise a source of compressed fluid (air in most cases), an internal tubing network, a valve assembly, and one or more ultrasonic whistles. In use, the compressed fluid source delivers fluid under pressure to the tubing network, the tubing network conveys the fluid to the whistle or whistles, and the valve assembly provides a means for controlling the volume of the fluid which is delivered to the whistle or whistles from the tubing network. Although the assembly of these devices is relatively simple and straight forward, it will be noted that difficulties may arise in customizing these devices to treat areas of varying sizes and dimensions or to rid an area of multiple types of pests. For example, the devices disclosed in the Quittner and Moe patents must be modified substantially to direct sound waves bi-directionally or multi-directionally. Further, it will be noted that the bonding or welding of the tubes comprising the ultrasonic pest control devices of the prior art is a labor intensive and time consuming process.
Accordingly, a need exists for an improved ultrasonic transmitter, and in particular, a need exists for an improved ultrasonic pest control device, which may be readily manufactured or modified to meet the needs of a given area of pest infestation.